RIYADH - Saudi Arabia was hosting a summit of Arab Gulf leaders Sunday as crises brew over a bitter diplomatic dispute with Qatar, the war in Yemen and the murder of Saudi journalist Jamal Khashoggi.

Qatari Emir Sheikh Tamim bin Hamad al-Thani was invited by Riyadh, which severed diplomatic ties with Doha in 2017 along with Bahrain and the United Arab Emirates (UAE), to the Gulf Cooperation Council talks.

In the emir’s place, Qatar announced it had sent State Minister for Foreign Affairs Soltan bin Saad al-Muraikhi to the annual event.

Saudi Arabia and its allies accuse Qatar of supporting terrorism and fostering close ties with their regional rival, Iran.

Doha — which announced this month it was quitting the Saudi-dominated OPEC oil cartel — denies the allegations, but the dispute has dragged on.

“Qatar has burned all the bridges enabling it to take back” its place within the GCC, Bahraini Foreign Minister Sheikh Khaled bin Ahmad al-Khalifa said in the run-up to the summit.

The GCC was formed in 1981 at the height of the Iraq-Iran war and two years after the Islamic revolution in Tehran sparked concern in Sunni-led Gulf states, many of which have sizable Shiite populations, including in Bahrain.

GCC Secretary-General Abdellatif al-Zayani has said the 39th summit in Riyadh would review ties with Iran after the U.S. reimposed an oil embargo and other sanctions on Tehran.

The U.S. administration, which pulled out from a landmark 2015 nuclear deal between Tehran and major world powers in May, has vowed to reduce Iran’s oil sales to zero.

Saudi Arabia, along with allies UAE and Bahrain, accuses Tehran of fomenting unrest among Shiites in the Gulf, and has backed the U.S. in piling pressure on Iran.

This contrasts with Kuwait and Oman which prefer normalizing ties with the Islamic republic. Kuwait has also been mediating between its Gulf partners and Qatar.

Sunday’s summit also comes as delegations from the Saudi-backed Yemeni government and Iran-linked Shiite rebels hold U.N.-brokered peace talks in Sweden.

Yemen’s capital has been held since 2014 by Houthi rebels who drove the government out and seized a string of ports.

The Yemeni government, based in the southern port city of Aden, has fought to drive back the rebels with support from a military coalition led by Riyadh and the UAE.

The conflict has killed nearly 10,000 people since 2015 when the coalition intervened, according to the World Health Organization, though some rights group say the toll could be five times higher.

The U.N. calls it the world’s worst humanitarian crisis, with as many as 20 million Yemeni’s facing acute food shortages.

This and images of massive devastation after coalition bombing raids on Yemen have sparked outrage among rights groups and prompted global players to demand an end to the conflict.

Pressure has been piling up on Riyadh to ease off its offensive, particularly an assault launched in June on the rebel-held port city of Hodeida, a key lifeline for aid entering Yemen.

The summit also comes with Saudi Arabia and its de facto ruler, Crown Prince Mohammed bin Salman, under mounting pressure over the murder of Washington Post columnist Khashoggi.

A critic of the crown prince, Khashoggi was killed by a hit squad in the Saudi Consulate in Istanbul on Oct. 2 in what Saudi Arabia described as a rogue operation.

Riyadh has steadfastly denied claims his grisly murder — he was reportedly dismembered — was ordered by the crown prince.